Stabilizing fins for missiles



Jan. 19, 1954 RlCHEY 2,666,387

STABILIZING FINS FOR MISSILES Filed Dec. 7, 1949 3 Sheets-Sheet l Jan. 19, 1954 D. M. RICHEY 2,666,337

STABILIZING FINS FOR MISSILES Filed Dec. 7, 1949 3 Sheets-Sheet 2 IN V EN TOR.

Mylo M. RIGHEV Jan. 19, 1954 D. M. RICHEY STABIL'IZING FINS FOR MISSILES 3 Sheets-Sheet 5 Filed Dec. 7, 1949 INVENTOR. DAV/0 6H5? missiles and planes or light bombers to Patented Jan. 19, 1954 STABILIZING 'FINS FOR MISSILES David M. Rickey, Devon, Cnn., assignor to United Aircraft Corporation, East Hartford, Comm, a corporation of Delaware Application December '7, 1949, Serial No. 131,530

'2 Claims. 1

This invention relates to stabilizing fins for more particularly to extensible stabilizing fins which may be retained in collapsed condition until needed for use whereupon they may automatically be extended so as to stabilize the missile in its fiight.

In the art of modern warfare the incendiary bomb has assumed increas importance for destroying enemy installations at the front line area as well as for the destruction of production facilities in the enemy home territory. One of the more effective bombs of this character has been made from the auxiliary expendable type of fuel tank which is normally carried by fighter increase their range of action. These tanks, when used to carry a reserve or additional supply of fuel, are releasably mounted beneath the wings of the plane so that they may be jettisoned after having been emptied thereby reducing wind resistance. the tanks then have served their purpose, the course of their flight in falling after being released from the plane is of no importance and, hence, no provision has been made to direct the course of their descent or stabilize their fall. However, when these tanks are adapted for incendiary use which is done by filling them with a highly inflammable jellylike substance it is essential that they be dropped with accuracy in order to insure that they strike the target. Because of the low wing clearance of the aircraft which usually carries "this type of bomb, it has been impracticable heretofore to provide suitable stabilizing fins that would enable the pilot to drop them'with any assurance that they would land in the target area.

The present invention is not limited for use with bombs such as those described above, but may be used with advantage in any application where space limitations preclude the use of the ordinary type of rigid stabilizing fins.

It is an object of the present invention, there- 'fore, to provide a stabilizing fin assembly "that normally occupies relatively little space when attached to a missile.

Another object "is to provide a fin assembly which may be kept folded against the body of the missile until required for use.

A further object is the provision of a.fin .assembly that will automatically open when the missile is launched.

A still further object is the provision of a demountable fin assembly that may be quickly and easily attached to a missile without-substantial modification thereof.

Since Other objects and attendant advantages will become more apparent from the following description taken in conjunction with the 8.0201111 panying drawings, in which:

Fig. *1 is a side elevation of one embodiment of the present invention attached to the rear of a drop type fuel container;

'Fig. 2 is a rear view of the embodiment illustrated in Fig. 1.

Fig. 3 isa :detailed view of one of the fins in unfolded or extended position;

Fig. 4 is a detailed cross section taken along a line substantially corresponding to line A l of Fig. 1 showing achannel which houses a foldable fin;

Figs. 5, 6 and 7 are enlarged cross sections through the lower member of a fin encasing channel and .takenalong linessubstantially corresponding 'toilines 25-5, 6-6 and Tl-l, respectively; and

Fig.8 is a transversesectional view taken along a line substantially corresponding to line ii-t of Fig. 3 showing themannerin whicha flexible fin panel is attached to its reinforcing arm.

In the embodiment illustrated in the drawings, the present invention is shown attached to a tank or 'bomb generally designated it. The assembly comprises a :forward 'mounting band i I adapted to fit about the girth of the bomb container and securely held in place by four clamps. Each of these-clamps includes an anchor member 12 that is formed. of a suitable length of strap metal with an upwardly extending inverted 'U- shaped :portion that is'slotted to receive 'thehead of a 'bolt is. This anchor member may be spot Welded or otherwise secured to thebomb zcasing. :A second clamping member M is formed with a *reentrant Itoe portion for insertion under the rear edgeof the mounting band it and has an upstanding portion with an opening adapted to receive the bolt 13. -A nut maybe threaded onto bolt t3 .to draw the parts together.

A rear mounting band l'5-has a-suitably tapered internal wall to closely :fit-about the rear of the .missilecasing. This band may be formed of a pair of semicircular members as shown so that the ribs on the missile casing may be gripped between the clamping elements of the band when drawn together by the securing bolts as shown in Fig. -2.

Equallyspaced around thebomb container are :four fin receiving channel members secured at their forward ends 'to the forward mounting band-H and at-theinrearends to the rearmounting'band 45. These-members l eextend generally longitudinally of the missile and may be secured to the respective mounting bands by any suitable means such as the screws and nuts shown in Figs. 5 and 6. Associated with each of the fixed channel members 16 is a fin arm ll of inverted channel cross section which when closed telescopes over the upwardly extending sides of its corresponding fixed channel it when the arms are folded against the body of the missile as shown in Figs. 1, 2 and 4. These fin arms are pivotally mounted on spaced upstanding cars it on the rear mounting band :5 and are adapted to swing outwardly to the position illustrated in Fig. 3 when the missile is launched.

Each fin arm 11 has secured to it a fin panel 19 (see Fig. 3) which is a substantially triangularly shaped sheet of flexible material such as cloth and has one edge attached to the fixed channel member 16 and another edge attached to the fin arms ii. The edges of the panels so secured are retained in place by fabric clamping strips 213 which are held in place by a number of spaced bolts and nuts as shown in Figs. 7 and 8, respectively. It will be noted that the edges of clamping strips 29 are curled over to provide a smooth surface so as to prevent chafing of the panel material when the fins are opened up as shown in Fig. 3, thus reducing the possibility of tearing or rupturing of the flexible material. The leading edge 21 of each of the panels may be reinforced with a length of cable 22 which is sewn in a fold of the material and has enlarged terminal portions for securing the ends of the cables to the fixed channel members and to the fin arms.

In order to provide uniform tension along the length of the lower and rear edges of the flexible material, rods 23 of suitable length may be inserted in the fold of the material adjacent the clamping strips as shown in Figs. 7 and 8. Affixed to each end of the channel members it and also to each end of the fin arms ll are cable anchor brackets 24 which are formed of a short length of strap metal and are provided with an inverted U-shaped portion that is suitably slotted to receive the cable 22.

The flexible material used for the fin panels may be cut with the weave running in the direction shown in Fig. 3 so as to provide the maximum strength and to prevent undue stretching when the fins are extended during flight of the missile. The corners of the panels may be reinforced by folding back the material a short distance if desired.

When a missile equipped with the present fin is stored or is being transported prior to launching, the fin arms ll are folded against the body of the missile and are securely held in place by means of a lashing cable 25 as shown in Figs. 1 and 2. The lashing wire is provided with a tensioning means such as turnbuckle 25 and fits into notches in the upper edges of guide clips 25a attached to the outside of the forward ends of the fin arms 11. The opposite ends of the lashing cable '25 are connected to tie plates 27. These plates have openings through which a safety wire 28 may be threaded to retain the lashing in place. This wire assures that tie plates 27 are secured together and cannot accidently separate to permit unintended opening of the fins. After the missile has been mounted in position on the plane, an arming wire 29 of the type commonly used on bombs is inserted into openings in the tie plates 27 and the safety wire 28 may then be removed. The other end of the arming wire 29 may be secured to the plane so that it is automatically withdrawn when the missile is released and has fallen a short distance.

Before the lashing 25 is applied, the flexible panels are folded over and encased within the space formed between the channel members l6 and the fin arms ll. When the missile starts its fall after having been released from the plane, the fin arms, no longer restrained by the lashing, are free to swing outwardly to the position shown in Fig. 3. Since the fin arms are mounted for free pivoting on their rear ends, the onrushing air entering the front end of the rectangular openings causes the arms to swing out to the projected position shown and the fiexible panels are stretched tight thus forming stabilizing fins for the missile.

It is to be understood, of course, that the foregoing description relates to only a preferred embodiment of the invention and that numerous modifications or alterations may be made therein without departing from the spirit and scope of the invention as set forth in the appended claims.

What is claimed is:

1. A foldable fin assembly for a missile comprising a pair of spaced mounting bands adapted to encircle the missile one forwardly of the other for securing the assembly to the missile, a plurality of channel members fixedly attached to the bands so as to extend fore and aft of the missile, a plurality of fin arms each hingedly mounted on a different one of said channel members at its aft end portion for swinging movement toward and away from said channel member and adapted to telescope over the sides of the channel member to form a fin enclosing casing, a fin panel enclosed in each casing, each fin panel having one edge secured to the channel member and another edge secured to the respective fin arm, a lashing for retaining the panels confined in their respective casings, and means for releasing said lashing after the missile is launched whereby the arms may swing out to extended position.

2. A stabilizer fin assembly for a missile comprising a fin enclosing member hingedly mounted on the missile at its after end portion for swinging movement between an outwardly extended position and a forwardly folded position, a flexible fin having an edge attached to the missile. said fin being collapsible within said member in its folded position, means for releasably securing said fin enclosing member in its folded position, the enclosing member being attached to the fin whereby release of said enclosing member serves to draw the fin into missile guiding position.

DAVID M. RICI-IEY.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 871,156 Aasen Nov. 19, 1907 1,243,542 Moore Oct. 16, 1917 1,294,924 Losin Feb. 18, 1919 1,318,926 Settle Oct. '14, 1919 1,879,840 Brandt Sept. 27, 1932 2,365,577 Moore Dec. 19, 1944 2,405,415 Eksergian Aug. 6, 1946 2,427,217 Lebherz et al. Sept. 9, 1947 2,430,896 Uhl et al Nov. 18, 1947 2,465,401 Skinner Mar. 29, 1949 FOREIGN PATENTS Number Country Date 41,371 France Oct. 11, 1932 

